[LucyKKG]

I think it really varies by campus tradition. Some schools are way more laid back than others.

At UC Santa Cruz, here's what we did:
Day 1 - Panhellenic Go Greek shirts, jeans, heels/some nice shoes
Day 2 - This year, it was matching polos with black pants and heels. Last year, we had matching t-shirts and jeans. I think the polos looked a lot nicer.
Day 3 - Black dresses, heels, minimal jewelry and badge

Some schools won't let the chapters have identical articles of clothing. At Santa Clara, the girls had a theme of colors for each day.
Day 1 - Navy blue or white dresses with yellow accessories (ribbons, jewelry, shoes, whatever)
Day 2 - White or black outfits with red accessories
I'm not sure what they did for pref night because I wasn't there.

There's a thread with pictures of some chapters during recruitment.